Red swamp crayfish(Procambarus clarkii)is a common freshwater shellfish product in China,especially in summer.Although China is considered to be one of the largest sources of global Hg emissions,and crayfish have been reported to accumulate Hg,there are few comprehensive studies regarding human Hg exposure due to crayfish consumption in China.This study evaluated potential exposure risk for Chinese consumers of P.clarkia.Total mercury(T-Hg)and methylmercury(MeHg)concentrations were determined in tail muscle of prepared and cooked P.clarkia collected from 25 restaurants throughout China.Average concentrations(wet weight basis)in 217 individual P.clarkii samples were 51.8±29.2ng/g T-Hg and 51.6±28.7 ng/g MeHg,respectively.Although concentrations varied between restaurants,mean values were relatively low with all samples below the national limit(500 ng/g).The estimated MeHg exposure risk for the general population in China from consuming crayfish was low,based on calculated hazard quotient(HQ < 0.01)and estimated daily intake(EDI = 0.96 ng/kg/d)of MeHg via crayfish consumption.These results suggest that P.clarkia crayfish consumption results in limited contribution to MeHg exposure for Chinese residents.However,local exposure for subsistence consumers may warrant further consideration.